javascript - Hidden Field Element with value as number always return string - Stack Overflow

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Consider the following code: HTML:

<input type="hidden" value=3 name="hello" id="test"/>
<input type="button" value="test me!" onclick="checkType();" />

JS:

function checkType(){
    var num = document.getElementById("test").value;
    alert(typeof num + ": " + num);

}

Or see this fiddle.

As you can observe, i placed a number for the value attribute of the HTML hidden element. I researched about the matter not find anything but to use typeof function to show what kind of data type the thing im lookin at is.

I dont know if it was valid as well anyway, placing an un-qouted number in the value attribute.

But the thing i want to acplish is, store a number hidden away from the UI, and then take it back and correctly show it as number back to the screen..

Been searching for about 3 days now, and rubber ducking* hasnt had any effect at all by now. And No JS gurus here in my office.

Best regards,

Consider the following code: HTML:

<input type="hidden" value=3 name="hello" id="test"/>
<input type="button" value="test me!" onclick="checkType();" />

JS:

function checkType(){
    var num = document.getElementById("test").value;
    alert(typeof num + ": " + num);

}

Or see this fiddle.

As you can observe, i placed a number for the value attribute of the HTML hidden element. I researched about the matter not find anything but to use typeof function to show what kind of data type the thing im lookin at is.

I dont know if it was valid as well anyway, placing an un-qouted number in the value attribute.

But the thing i want to acplish is, store a number hidden away from the UI, and then take it back and correctly show it as number back to the screen..

Been searching for about 3 days now, and rubber ducking* hasnt had any effect at all by now. And No JS gurus here in my office.

Best regards,

• javascript
• html

Share Improve this question Follow asked Sep 29, 2014 at 3:18 Fasev MoweasckFasev Moweasck 10122 gold badges33 silver badges1414 bronze badges 6

• 6 All input values are strings. Whatever value you assign it will be converted to a string. – p.s.w.g Commented Sep 29, 2014 at 3:18
• convert it back to to an integer. developer.mozilla/en-US/docs/Web/JavaScript/Reference/… – beaglebets Commented Sep 29, 2014 at 3:22
• hi sirs, do you have any idea how can i make things dynamic converting things to int when they are int, otherwise as string. used typeof function just to fail – Fasev Moweasck Commented Sep 29, 2014 at 3:38
• Presumably you should know which values should be numbers and which should be strings. Therefore you should apply this knowledge to your code. – Lee Taylor Commented Sep 29, 2014 at 3:40
• Use parseInt(document.getElementById("test").value,10) for integers or parseFloat( document.getElementById("test").value) for decimal values - noe the casing of the mands. – user2417483 Commented Sep 29, 2014 at 3:47

 |  Show 1 more ment

1 Answer 1

Sorted by: Reset to default 9

As p.s.w.g said, input values are strings. If you really want to convert it to Number type, just use the unary + operator.

var num = +document.getElementById("test").value;

Updated fiddle here: http://jsfiddle/0h61xwkg/3/

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